When we are talking about sustainability in the construction sector, people will normally relate to the new development whatever the scale it is. We may talk in the context of urban planning and urban regeneration for developing a livable city with cleaner air, greener environment and better leisure and cultural facilities. We may also discuss something about greening features and provisions in the building design to save energy and reduce carbon emissions. People will seldom, even if not none, relate the topic of sustainability to building rehabilitation.
Every building shall have its design life and the building life span will depend on various factors including the use of materials and the use of building. With the proper maintenance and upkeep and also assume there is neither abuse use nor damage, buildings in the reinforced concrete structural frame shall rest on land for more than hundred years. Buildings here in the territory are however staying less than the design life, not for the reason that they are approaching the end of their life, but for the other reasons that they are forced to end their life. Buildings are in fact not necessary physically obsolescent, but may be classified as economic obsolescent that lead to the decision for putting the end of the building. Buildings under such classification might be demolished to vacant the land for another development. To certain extent, the development mode is in this pattern in the second half of the last century at the time when our home place is in the expansion stage of economic growth.
Demolition results in the generation of construction waste. Is it considered as a kind of wastage if building can still be able to serve. It is yet to reach the end of its life and the building can still perform. Other than the option to carry out demolish and rebuild option, building owner can choose to carry out conversion, alteration and addition. New use and economic activities will be introduced to generate new life of building. This can save tons of construction waste arising from the building demolition. The construction period for building conversion is comparatively shorter than that for new erection, energy consumption and the impact to the environment shall be less as well. If we define sustainability as the practice of maintaining processes of productivity to meet the current needs without degrading or endangering the nature, building rehabilitation shall be a good demonstration of sustainability.
Structure and fabric of building are subject to weathering on their exposure to weather during the life of building. It is also a natural chemical process for some sort of deterioration of reinforced concrete structures in the form of spalling on its exposure to the environment. Building facilities may be outdated and cannot serve in the good way to the occupants as time elapsed. Technology advances with time and there is some sort of equipment and facilities which are not in the market at the time of the building erection and owners/occupants may wish to upgrade the provision or even to fix the new provision for the amenity and better enjoyment after the use of their buildings for over decades.
Take a typical example for building rehabilitation works of tenement buildings in the territory, typical work scope shall include the repair of spalled concrete; refurbishment of external wall including repainting; replacement of above-ground drainage system; re-plumbing work and possibly fixing of new intercom system as a security measures which shall be not available at the time of building erection half century ago.
Proper maintenance and upkeep is necessary to assure the good and serviceable condition of building. With the good concept by building owners for building care and with appropriate professional input by consultants/contractors, our built assets shall be able to keep as expected and design value. As mentioned above, building rehabilitation shall be considered as a good demonstration of sustainability.
Sr Peter W.F. DY
BSc (Hons); MA (ArbDR); MSc (MEN); FHKIS
Council Member of Building Surveying Division
Hong Kong Institute of Surveyors (HKIS)